Background Tasks

Use q.run() to execute functions in the background, in-process.

import time
import random
from h2o_wave import main, app, Q, ui
def blocking_function(secs) -> str:
time.sleep(secs) # Blocks!
return f'Done waiting for {secs} seconds!'
@app('/demo')
async def serve(q: Q):
if q.args.start:
q.page['form'] = ui.form_card(box='1 1 12 10', items=[ui.progress('Running...')])
await q.page.save()
seconds = random.randint(1, 6)
# DON'T DO THIS!
# This will make your app unresponsive for some time:
# message = blocking_function(seconds)
# Do this instead:
message = await q.run(blocking_function, seconds)
q.page['form'] = ui.form_card(box='1 1 12 10', items=[ui.message_bar('info', message)])
await q.page.save()
else:
q.page['form'] = ui.form_card(box='1 1 12 10', items=[ui.button(name='start', label='Start')])
await q.page.save()

Tags: โ€‚background_tasks